/Engine/Plugins/Online/OnlineSubsystem/Source/Public/Interfaces/VoiceInterface.h
Reads local voice data for the specified local talker. The size field contains the buffer size on the way in and contains the amount read on the way out
0 upon success, an error code otherwise
uint32 ReadLocalVoiceData ( uint32 LocalUserNum, uint8 * Data, uint32 * Size )